If a non-Muslim performs salah (prayers), does he become a Muslim?

Suppose a person, who believes in one god, starts doing salah (prayers) as he loves Allah and his messenger and trusts them, but he does not accept Islam because of family and social problems. He does salah, pays zakkah, and does not break the rules which Allah has given to his messengers. **Question:** When he prays 5 times a day, he reads the shahadah after wudu and in tashahud as we all do. Has he become a Muslim by reading shahadah even though he does not want to accept Islam?